1 files changed, 133 insertions, 0 deletions
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cpp
new file mode 100644
index 000000000000..ef14fb704eed
--- /dev/null
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cpp
@@ -0,0 +1,133 @@
+//===-- sanitizer_stacktrace.cpp ------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is shared between AddressSanitizer and ThreadSanitizer
+// run-time libraries.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common.h"
+#include "sanitizer_flags.h"
+#include "sanitizer_stacktrace.h"
+
+namespace __sanitizer {
+
+uptr StackTrace::GetNextInstructionPc(uptr pc) {
+#if defined(__sparc__) || defined(__mips__)
+  return pc + 8;
+#elif defined(__powerpc__) || defined(__arm__) || defined(__aarch64__)
+  return pc + 4;
+#else
+  return pc + 1;
+#endif
+}
+
+uptr StackTrace::GetCurrentPc() {
+  return GET_CALLER_PC();
+}
+
+void BufferedStackTrace::Init(const uptr *pcs, uptr cnt, uptr extra_top_pc) {
+  size = cnt + !!extra_top_pc;
+  CHECK_LE(size, kStackTraceMax);
+  internal_memcpy(trace_buffer, pcs, cnt * sizeof(trace_buffer[0]));
+  if (extra_top_pc)
+    trace_buffer[cnt] = extra_top_pc;
+  top_frame_bp = 0;
+}
+
+// Sparc implemention is in its own file.
+#if !defined(__sparc__)
+
+// In GCC on ARM bp points to saved lr, not fp, so we should check the next
+// cell in stack to be a saved frame pointer. GetCanonicFrame returns the
+// pointer to saved frame pointer in any case.
+static inline uhwptr *GetCanonicFrame(uptr bp,
+                                      uptr stack_top,
+                                      uptr stack_bottom) {
+  CHECK_GT(stack_top, stack_bottom);
+#ifdef __arm__
+  if (!IsValidFrame(bp, stack_top, stack_bottom)) return 0;
+  uhwptr *bp_prev = (uhwptr *)bp;
+  if (IsValidFrame((uptr)bp_prev[0], stack_top, stack_bottom)) return bp_prev;
+  // The next frame pointer does not look right. This could be a GCC frame, step
+  // back by 1 word and try again.
+  if (IsValidFrame((uptr)bp_prev[-1], stack_top, stack_bottom))
+    return bp_prev - 1;
+  // Nope, this does not look right either. This means the frame after next does
+  // not have a valid frame pointer, but we can still extract the caller PC.
+  // Unfortunately, there is no way to decide between GCC and LLVM frame
+  // layouts. Assume LLVM.
+  return bp_prev;
+#else
+  return (uhwptr*)bp;
+#endif
+}
+
+void BufferedStackTrace::UnwindFast(uptr pc, uptr bp, uptr stack_top,
+                                    uptr stack_bottom, u32 max_depth) {
+  // TODO(yln): add arg sanity check for stack_top/stack_bottom
+  CHECK_GE(max_depth, 2);
+  const uptr kPageSize = GetPageSizeCached();
+  trace_buffer[0] = pc;
+  size = 1;
+  if (stack_top < 4096) return;  // Sanity check for stack top.
+  uhwptr *frame = GetCanonicFrame(bp, stack_top, stack_bottom);
+  // Lowest possible address that makes sense as the next frame pointer.
+  // Goes up as we walk the stack.
+  uptr bottom = stack_bottom;
+  // Avoid infinite loop when frame == frame[0] by using frame > prev_frame.
+  while (IsValidFrame((uptr)frame, stack_top, bottom) &&
+         IsAligned((uptr)frame, sizeof(*frame)) &&
+         size < max_depth) {
+#ifdef __powerpc__
+    // PowerPC ABIs specify that the return address is saved at offset
+    // 16 of the *caller's* stack frame.  Thus we must dereference the
+    // back chain to find the caller frame before extracting it.
+    uhwptr *caller_frame = (uhwptr*)frame[0];
+    if (!IsValidFrame((uptr)caller_frame, stack_top, bottom) ||
+        !IsAligned((uptr)caller_frame, sizeof(uhwptr)))
+      break;
+    uhwptr pc1 = caller_frame[2];
+#elif defined(__s390__)
+    uhwptr pc1 = frame[14];
+#else
+    uhwptr pc1 = frame[1];
+#endif
+    // Let's assume that any pointer in the 0th page (i.e. <0x1000 on i386 and
+    // x86_64) is invalid and stop unwinding here.  If we're adding support for
+    // a platform where this isn't true, we need to reconsider this check.
+    if (pc1 < kPageSize)
+      break;
+    if (pc1 != pc) {
+      trace_buffer[size++] = (uptr) pc1;
+    }
+    bottom = (uptr)frame;
+    frame = GetCanonicFrame((uptr)frame[0], stack_top, bottom);
+  }
+}
+
+#endif  // !defined(__sparc__)
+
+void BufferedStackTrace::PopStackFrames(uptr count) {
+  CHECK_LT(count, size);
+  size -= count;
+  for (uptr i = 0; i < size; ++i) {
+    trace_buffer[i] = trace_buffer[i + count];
+  }
+}
+
+static uptr Distance(uptr a, uptr b) { return a < b ? b - a : a - b; }
+
+uptr BufferedStackTrace::LocatePcInTrace(uptr pc) {
+  uptr best = 0;
+  for (uptr i = 1; i < size; ++i) {
+    if (Distance(trace[i], pc) < Distance(trace[best], pc)) best = i;
+  }
+  return best;
+}
+
+}  // namespace __sanitizer